In modern computing environments, computer systems are often interconnected using local area networks, also referred to as LANs. LANs allow computer-to-computer and processor-to-processor communications. In many environments, this networking concept is extended so that multiple LANs are networked together through the use of intermediate nodes or gateways. Inherent in the communication between computers or data processing systems is a protocol which transfers data and control information necessary for proper communication of the systems. When this communication protocol is utilized, the information is transferred in packets, or frames. Within these packets or frames, communications-related control information and data values are typically transmitted.
The data information is the actual data that one device is communicating to another over the LAN. The control information is the information required by the communications protocol to send the packet over the network from one computing system to another. Such control information is usually one of a "header" or a "trailer" of a packet. Control information in the header is generally interpreted by a communications protocol processor before the packet is passed on to a receiving application. Control information typically included in the header of a packet includes information such as a source address, a destination address and routing information. Furthermore, control information in a trailer of a packet generally includes cyclic redundancy checking (CRC) information. Typically, a transmitting data processing system sends a packet of data information and then appends to it an appropriate computed CRC value. At the receiving data processing system, a receiving node will calculate its own CRC value and compare its CRC value with the CRC value received from the data transmitting system. When the two are different, this indicates that an error occurred during transmission of the data packet.
While this protocol is typically used by most data processing applications, this protocol also limits the performance which may be achieved by a system. The use of the CRC value typically requires at least the final four bytes of a packet, or frame, to be used to provide a CRC value. In a communications environment which has been developed and utilized extensively, every savings and performance improvement is necessary and significant. Therefore, the requirement that the final four bytes of a frame always be used for providing a CRC value may prove to be a necessary evil.
Therefore, a need exists for a communication system which provides for improvements in a communication system involving a LAN, while still maintaining the error checking capability of the CRC value.